The present invention relates generally to steering systems for automotive vehicles. More specifically, the present invention relates to power and manual rack and pinion steering systems for automotive vehicles.
Rack and pinion power steering systems are commonly used in automotive vehicles. To prevent excessive noise during operation of the steering system, the pinion should be oriented in a desired direction so that upon rotation of the pinion, the rack moves in the desired manner. During operation that position should be maintained. If proper positioning is not maintained, undesirable noise may be generated.
Commonly, the rack and pinion housings are formed together in a single casting. The castings are typically formed in a foundry. One drawback to such systems is that steering systems are typically manufactured for use in a variety of vehicles. Each vehicle, however, may require a slightly different variation in the position of the rack with respect to the pinion. Therefore, new molds and new castings must be formed. Another drawback to this process is that it is very expensive to implement the additional mold to form the housing.
Also in conventional power steering systems, the pinion is positioned at one end of the rack while the other end of the rack is supported by a bushing. One problem with this configuration is that the unsupported end may cause mechanical noise due to the lack of support of the rack.
It would therefore be desirable to provide a power steering system that allows flexibility in manufacturing by allowing different positions of the rack with respect to the pinion without expensive processing.
It is therefore one object of the invention to provide a power steering system that is easily manufacturable and allows easy mechanical alignment of the rack with respect to the pinion. It is a further object of the invention to provide a steering system that reduces noise during operation.
In one aspect of the invention, a steering system comprises a first tube having a first end and a second end and a first opening positioned between the first end and the second end. A second tube has a second opening alignable with the first opening. The first tube and second tube are coupled together at the first opening and the second opening. A rack is positioned within the first tube and a pinion is positioned within the second tube. A first bushing is positioned within the first tube adjacent to the first end. A second bushing is positioned within the first tube adjacent to the second end. The first and second bushings support the rack within the first tube.
In a further aspect of the invention, a method of forming a steering system comprises the steps of:
cutting a first opening in a first tube between a first end and a second end to expose a first fillet;
cutting a second opening in a first tube to expose a second fillet;
positioning the first fillet against the second fillet so that the first tube is positioned in a predetermined orientation with respect to the second tube;
fixedly fastening the first fillet and the second fillet;
placing a rack within the first tube;
placing a pinion within the second tube; and
aligning the pinion with the rack.
One advantage of the invention is that a good return force may be provided by the present invention. Another advantage of the invention is that the configuration may be made for both manual and power assisted steering systems. Yet another advantage of the invention is that the system may be easily modified to provide different angles between the rack and pinion without having to form complex casting molds.
Other objects and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims.